1. Field of the Invention
The present invention relates to a digital image display, and more particularly, it relates to a digital image display comprising a display screen portion displaying a digital image signal.
2. Description of the Background Art
A digital image display comprising a display screen portion displaying a digital image signal is known in general, as disclosed in each of Japanese Patent Laying-Open Nos. 10-63234 (1998), 2000-47649 and 2000-47648, for example.
Each of the aforementioned Japanese Patent Laying-Open Nos. 10-63234 and 2000-47649 discloses a digital image display comprising an analog-to-digital conversion circuit, an image start/end coordinates detection circuit, a display control circuit and an image display portion (display screen portion). The digital image display described in each of Japanese Patent Laying-Open Nos. 10-63234 and 2000-47649 is so formed as to decide the optimum phase value when controlling the phase of a digital image signal output to the image display portion by obtaining the arithmetic mean (intermediate value) of a reference phase value and a phase value obtained by changing the reference phase value for horizontally shifting the left end position (coordinates) of a pixel region having image data by a prescribed distance (number of pixels).
The aforementioned Japanese Patent Laying-Open No. 2000-47648 proposing a digital image display discloses an automatic display position control system of controlling a display position of an image signal (image) on a screen display connected to a body screen output device by transmitting/receiving respective status data between the screen display and the body screen output device outputting the image signal to the screen display. According to the automatic display position control system disclosed in Japanese Patent Laying-Open No. 2000-47648, the display position of the image signal (image) on the screen display connected to the body screen output device can be controlled by changing setting in the body screen output device on the basis of the status data of the screen display.
In the conventional digital image display proposed in each of the aforementioned Japanese Patent Laying-Open Nos. 10-63234 and 2000-47649, however, the intermediate value according to the arithmetic mean of the reference phase value and the phase value obtained by changing the reference phase value for horizontally shifting the left end position (coordinates) of the pixel region by the prescribed distance (number of pixels) is regarded as the optimum phase value. Therefore, a position (edge portion) maximumly displaying the difference between the colors of adjacent pixels by phase control is conceivably not strictly specified. Thus, the optimum phase value is not exactly obtained.
In the conventional automatic display position control system proposed in the aforementioned Japanese Patent Laying-Open No. 2000-47648, the body screen output device connected with the screen display controls the image signal (display image) on the basis of the communicative function between the screen display and the body screen output device. If a screen display incapable of communicating with the body screen output device (image signal output device) is connected to the body screen output device, therefore, the image signal (display image) output to a display screen portion of the screen display cannot be controlled.